Pop Art originated in London in the 1950s with young artists appropriating the mass-produced imagery of popular culture. The movement developed independently in the United States, with Jasper Johns’ use of recognizable symbols and Robert Rauschenberg’s incorporation of everyday objects laying the theoretical groundwork. American Pop Art developed into a coherently recognizable style by the 1960s. American Pop Art further complicated existing definitions of “high” and “low” art, incorporating—or blatantly appropriating—mass-produced products, iconic celebrities, everyday objects, comic books, and photographs. Artists including Roy Lichtenstein and Andy Warhol appropriated not only the imagery of mass material culture but also the intentionally simplified techniques of industrial printing resulting in flattened images that belie the surface of the canvas. Other influential American Pop Artists include: Tom Wesselmann, Jim Dine, James Rosenquist, Wayne Thiebaud, and Robert Indiana, recognized for his meticulous reproductions of typography and graphic design as well as Ed Ruscha, for his emphasis on the car culture of Southern California.